1. Field of the Invention
The present invention relates to a wafer support member used to hold an object to be processed such as a semiconductor wafer in a film forming system such as PVD system, a CVD system, an ion plating system, a vapor deposition system, or an etching system (semiconductor wafer processing system), and a semiconductor equipment using the above wafer support member. More specifically, the present invention relates to a penetrated feeding structure in which an electrode provided on the vacuum side is connected to a terminal provided on the air side.
2. Description of the Related Art
In general, the semiconductor wafer processing system comprises a wafer support member, that is, a processing chamber on which a susceptor is mounted, and the wafer support member is used to support a wafer in the processing chamber. The wafer support member comprises various components to hold the wafer at a predetermined position on the wafer mount surface of the wafer support member to fix the wafer, and various components to heat and/or cool the wafer. In addition, the wafer is fixed by a mechanical fixing or an electrostatic chucking. Space above the wafer support member on which the wafer is processed in the processing chamber is kept in high vacuum in general and space below the wafer support member is kept at atmospheric pressure.
A Japanese Unexamined Patent Publication No. 1998-326823 discloses a penetrated feeding structure 110 which connects an electrode provided on the vacuum side to an electrode on the air side in such wafer support member (FIGS. 8A and 8B). The wafer support member 100 comprises a periphery mounting flange 102 having a plurality of holes 106 and an electrode 108 in the center of a mount surface 104 as shown in FIG. 8.
FIG. 8B is a partially sectional view showing the wafer support member 100 taken along line 200-200 in FIG. 8A. The penetrated feeding structure body 110 in the wafer support member 100 has a structure as will be described below and it is used to supply a power from the air side 72 to the conductive electrode arranged on the vacuum side 70 and the electrode 108 fixed to the mount surface 104 of the wafer support member 100.
The penetrated feeding structure body 110 comprises a plurality of via holes 208 (2081, 2082, 2083, and 2084, for example) arranged in the plate-shaped ceramic body vertically, a plurality of conductive layers 206 (2061, 2062, 2063, 2064, and 2065, for example) connected to each other through the via holes 208, and a feeding terminal 214 connected to at least one of the conductive layers 206. The feeding terminal 214 is connected to the electrode 206 from the air side 72.
In addition, a Japanese National Publication of International Application No. 2002-505036 discloses a wafer support member 600 having an electrostatic chuck mechanism as shown in FIG. 9A. FIG. 9B is a sectional view taken along line 800-800 in FIG. 9A. The wafer support member 600 comprises a gas supply via hole 606 through which a heat transmission medium (argon or helium gas, for example) is supplied to space between a wafer 202 and a chuck surface 626 of the wafer support member 600. In addition, the wafer support member comprises an electrode 604 on an inner surface and an electrode 624 on an outer surface in a wafer detection system. According to this wafer support member 600, the inner-surface electrode 604 is connected to a detection circuit 650 through a surface conductor 622 provided on an inner surface of the gas supply via hole 606. The surface conductor 622 is formed on an inner surface of the gas supply via hole 606 up to a rear surface of the wafer support member 600, and connects the inner-surface electrode 604 formed on the mount surface 626 of the wafer support member 600 to the detection circuit 660 provided below the wafer support member 600. For example, when the inner-surface electrode 601 and the outer-surface electrode 624 are used for detecting the wafer, an electrode of one end of the wafer detection circuit 650 is electrically connected to the inner-surface electrode 604.
However, according to the wafer support member described in the Japanese Unexamined Patent Publication No. 1998-326823, since the connecting structure body which connects the electrode fixed to the mount surface of the plate-shaped ceramic body to the electrode provided on the other surface of the plate-shaped ceramic body is manufactured by forming the via holes in each of the plurality of ceramic bodies which constitute the plate-shaped ceramic body and Connecting the respective via holes to the respective conductive layers, the structure of the connecting structure body is complicate and its manufacturing process becomes naturally complicated.
In addition, since it is necessary to provide an evacuating via hole separately from the connecting structure body, its structure becomes more complicated.
Furthermore, since the structure of the connecting structure body is complicated, the via hole formed in the ceramic body could not be sufficiently connected to the conductive layer. When these are preferably connected, a function to detect the existence of the wafer or a function to detect whether the wafer is damaged or not cannot be satisfactorily implemented.
Still furthermore, according to the structure described in the Japanese National Publication of International Application No. 2002-505036, although a pipe is arranged on the rear surface of the wafer support member so as to be connected to the via hole for evacuation in general, a flange part of the pipe and a wiring which connects the electrode of one end of the wafer detection apparatus to a part of the surface conductor 622 cross to each other and a void is likely to be generated in the vicinity of the wiring at this crossed part. Therefore, the vacuum tightness could be broken in the pipe and on the mount surface of the wafer support member 600. In addition, the stress does not become uniform due to the thermal expansion difference between the brazed part and the wiring and distortion after the thermal cycles concentrates on this brazed part. Thus, after the heating and cooling operations were repeated, a crack 641 could be generated at the brazed part 640 between the wiring and the conduction layer on the inner surface of the gas supply hole as shown in FIG. 10. Thus, the conduction between the conductive layer and the wafer detection apparatus could not be implemented and vacuum tightness could be broken also at the junction part between the pipe and the via hole like the above.